Debt Payoff Calculator: Snowball vs Avalanche
Add your debts and a monthly budget to compare two payoff strategies side by side: the debt snowball (smallest balance first) and the debt avalanche (highest interest rate first). See months to debt-free, total interest paid, and the payoff order for each debt under both methods.
- Interest Saved with Avalanche
- ...
- Avalanche: Months to Debt-Free
- ...
- Avalanche: Total Interest Paid
- ...
- Snowball: Months to Debt-Free
- ...
- Snowball: Total Interest Paid
- ...
Total Debt Balance Over Time
- Snowball
- Avalanche
Not enough data yet to plot this chart.
Assumptions
- Interest accrues monthly on each debt's remaining balance, at that debt's entered APR divided by 12. This is a simplified monthly-compounding model, not a substitute for your actual card or loan's specific compounding and payment-posting rules.
- Assumes your interest rates stay fixed and you take on no new charges or new debt on these accounts for the entire payoff period. In practice, rates can change, especially on variable-rate credit cards, and new borrowing is common, both of which would change the real payoff time.
- Assumes your full monthly budget is applied every month with no missed or late payments, and that as each debt is paid off, its minimum payment rolls into the amount directed at the next target debt under both strategies, the mechanic that gives the snowball method its name.
- The debt avalanche method mathematically produces the lowest, or tied, total interest of the two strategies for a given budget, since it always targets whichever balance is accruing interest fastest. It does not always finish in fewer months, and the gap between the two methods can be small or large depending on your specific balances and rates.
- Behavioral research on debt repayment (see sources) has found that concentrating payments on a single account, particularly the smallest one, is associated with people staying more motivated to keep paying down debt than spreading payments evenly across accounts. That is a documented pattern in that research, not a guarantee about how any individual will behave.
- This is a planning estimate only, not financial advice. It does not account for taxes, retirement contributions, emergency savings, fees, or other financial priorities that may compete with debt payoff.
Sources
- Consumer Financial Protection Bureau, "How to reduce your debt," published July 16, 2019, updated 2026: describes both the highest-interest-rate (avalanche) and smallest-balance (snowball) repayment strategies used here.
- Kettle, Keri L., Remi Trudel, Simon J. Blanchard, and Gerald Haubl. "Repayment Concentration and Consumer Motivation to Get Out of Debt." Journal of Consumer Research 43, no. 3 (2016): 460-477. Found that concentrating repayment on a single account, especially the smallest one, increased consumers' motivation to become debt-free compared with spreading payments evenly across accounts.
How the simulation works
Each month, interest is added to every debt's remaining balance. Then the minimum payment is made on every debt still open. Whatever is left of your budget after all minimums, the surplus, goes entirely toward one target debt: the smallest balance under snowball, or the highest interest rate under avalanche. When a debt is paid off, its minimum payment joins the surplus pool for the next target, so the amount attacking your target debt grows every time one is eliminated. Both strategies use your exact same monthly budget; only the order debts get attacked in changes.
Why avalanche always wins on interest, and why snowball still has a case
Avalanche always produces the lowest, or tied, total interest, because it always directs extra money at whichever balance is costing you the most. But a large body of behavioral research on debt repayment has found that people who concentrate payments on their smallest balance, the snowball approach, tend to stay more motivated and keep paying consistently, likely because clearing a whole account feels like more visible progress than shrinking a larger one. When the dollar difference between the two methods is small relative to your total debt, the method you are actually likely to stick with every month may matter more than the one that is mathematically optimal.
Worked example
Three debts, a credit card, a car loan, and a personal loan, totaling $19,000, with a $600 monthly budget covering $440 in combined minimum payments.
With $600 a month, $160 above the $440 in combined minimums, avalanche pays off the credit card first (month 19, the highest rate at 22.99%), then the personal loan (month 24), then the car loan (month 37), for $2,928 in total interest. Snowball pays off the smaller personal loan balance first (month 13), then the credit card (month 25), then the car loan (month 38), for $3,232 in total interest over 38 months. Avalanche saves about $304 in interest and finishes a month sooner here, a real but fairly modest difference against $19,000 in total debt.
Frequently asked questions
Can I use this debt payoff calculator for credit card debt?
Yes. Add one row per credit card, or any other debt, with its balance, APR, and minimum payment, and set your total monthly budget. Credit cards are exactly the kind of high-interest, revolving debt where the avalanche method tends to save the most, since balances like these usually carry the highest rates in a typical debt list.
How does the debt snowball calculation work here?
The snowball method pays the minimum on every debt, then puts all remaining budget toward whichever balance is smallest, regardless of its interest rate. Once that debt is paid off, its minimum payment rolls into the amount going toward the next-smallest balance, and so on, which is where the method gets its name.
What does the debt avalanche method do differently?
Avalanche uses the same minimum-payments-plus-rollover mechanics as snowball, but targets whichever debt has the highest interest rate first instead of the smallest balance. Because it always attacks the balance costing you the most in interest, it produces the lowest, or tied, total interest of the two strategies for the same budget.
Snowball vs avalanche: which one actually saves more money?
Avalanche never costs more than snowball in total interest, and usually costs less, since it always targets the most expensive debt first. This calculator shows the exact interest difference for your own numbers. When that difference is small, research on repayment behavior suggests the method you are more likely to actually stick with may matter more than the one that is technically optimal.
How do extra payments factor into this debt payoff calculator?
Your monthly budget is the total available for all debts, including minimum payments, so any amount above the sum of your minimums is the extra payment. This calculator directs that entire extra amount at one target debt at a time, your smallest balance under snowball or your highest rate under avalanche, rather than splitting it evenly across every debt.
Why use this instead of a debt payoff spreadsheet in Excel?
A spreadsheet can do the same month-by-month math, but it takes setting up formulas for interest accrual, minimum payments, and rollover logic yourself, then re-checking them every time you add or remove a debt. This calculator runs that same simulation instantly, for both strategies side by side, entirely in your browser, with nothing you enter saved or uploaded.
Related calculators
- Auto Loan Payoff Calculator
Find out how much sooner you'd pay off your car loan, and how much interest you'd save, by adding extra principal payments. Compare an extra monthly amount or a one-time lump sum against your standard schedule, and check whether your loan's financing type actually lets early payments save you anything.
- Mortgage Extra Payment Calculator
Find out how much sooner you'd pay off your mortgage, and how much interest you'd save, by adding extra principal payments. Compare extra monthly amounts, a one-time lump sum, or switching to biweekly payments against your standard schedule.
- Net Worth Calculator
Add what you own and what you owe to see your net worth: total assets minus total liabilities. It also splits your assets into liquid (cash you could access within days) and illiquid (retirement accounts, your home, a vehicle) so you can see your liquid net worth alongside your overall one.